The present invention relates to an arrangement for driving a wheel of a vehicle comprising a planetary gear set, which in turn comprises a planet carrier, at least one surface of the planet carrier having a toothed structure, the arrangement comprising a power transmission part, at least one surface of the power transmission part having a toothed structure which corresponds to the toothed structure of the planet carrier surface and an extent which corresponds to the extent of the toothed structure of the planet carrier surface, and the toothed structures of the planet carrier and the power transmission part intermeshing with one another. The invention also relates to the planet carrier per se.
The invention more specifically relates to a so-called final drive, or hub-mounted reduction gear. The wheel is then arranged rotationally locked on a hub and the planetary gear set is connected between a drive shaft and the hub. The drive shaft is driven by an angular gear, or center gear, which is in turn driven by the vehicle engine by way of a transmission system.
Arranging a planetary gear set on each drive wheel in this way produces a reduction in rotational speed from the drive shaft to the hub and an increase in torque from the drive shaft to the hub.
The arrangement is particularly intended for applications in a plant vehicle such as a wheel loader, a dumper or the like. The invention could also be used, however, in other heavy vehicles such as trucks and buses.
W099/03699 describes a planetary gear set for a vehicle.
The hub comprises an axially projecting axle part which is arranged in a through-hole in the planet carrier. The hole has internal splines and the axle part has external splines for producing rotational locking relative to one another. A plate having a greater radial extent than the axle part is arranged axially inside the planet carrier and is connected to the hub by way of a plurality of screws through holes in the plate and the axle part of the hub. This ensures that the hub is axially fixed in relation to the planet carrier.
It is desirable to provide an arrangement for driving a wheel of a vehicle which is cost-effective to produce and which creates the prerequisites for a long service life.
In accordance with an aspect of the present invention, a surface of the planet carrier provided with a toothed structure extends in such a way that the toothed structure is exposed in the axial direction of the planet carrier.
The toothed structure forms a ridge-valley configuration having elongate, parallel ridges and valleys. The term exposed in the axial direction is intended to signify that at least some of the ridges are visible from above and are accessible for engagement in the axial direction.
The backs of the ridges therefore face outwards in the axial direction of the planet carrier. The term exposed in the axial direction is thus not intended to signify that the cross-sectional shape of the toothed structure is only visible from the side, but that at least some of the backs of the teeth are visible viewed from the axial direction of the planet carrier.
According to an aspect of the invention the planet carrier with toothed structure extends parallel to a plane. This creates the prerequisites for easy production of the toothed structure by milling parallel grooves in the surface.
According to a development of the preceding aspect the planet carrier surface with toothed structure extends parallel to a plane which is at least substantially at right angles to the axial direction of the planet carrier. This creates the prerequisites for an engagement that is beneficial in terms of fatigue strength.
It is desirable to provide a planet carrier which is cost-effective to produce and which affords a long service life in the intended application of a planetary gear set.
According to an aspect of the invention, at least one surface of the planet carrier has a toothed structure for meshing with a power transmission part, and said surface provided with a toothed structure extends in such a way that the toothed structure is exposed in the axial direction of the planet carrier.
Further advantageous embodiments and advantages of the invention will emerge from the following description.